Re: [Nasm-users] calling 'C' functions

[zak100 <zul...@ya...>]

Hi Peter and Frank,
I am able to compile the code after removing the brackets but now I am
getting prob with ld.
D:\nasm prog>nasm -f elf test_kernel2.asm -o test.o

D:\NASMPR~1>ld -o kernel.exe test.o main1.o
test.o:(.text+0xa): relocation truncated to fit: R_386_16 against `.text'

D:\NASMPR~1>dir k*
 Volume in drive D is New Volume
 Volume Serial Number is 70FD-1D2C

 Directory of D:\NASMPR~1

File Not Found

D:\NASMPR~1>

I downloaded alib but some files were missing. Thanks for your attention but
I am still looking for more help on this using ld.

In the meantime, i would be looking for alib again.

Zulfi.


Frank Kotler-3 wrote:
> 
> H. Peter Anvin wrote:
>> zak100 wrote:
>>> Hi,
>>> I am trying to call 'C" functions from my tiny kernel code. Can somebody
>>> plz
>>> help me with this?
>>> ; call c function
>>> extern [_K_main]
>> 
>> That should be
>> 
>> 	extern _K_main
>> 
>> No brackets...
> 
> Now why haven't I seen my reply to Zulfi... in which I point out that 
> "-f bin" isn't going to like it without the brackets, either? Maybe 
> "nasm-users" doesn't like me...
> 
> Anyway... I tried the following experiment... Since I don't "do" C 
> (much), I made up a "fake" kmain, which simply prints the letter "K" on 
> the screen and returns. Assembled with "-f obj". Added a "..start:" 
> label to "test_kernel2", and assembled that with "-f obj". Since I've 
> got Alink working under Linux, I tried to link 'em with "alink -oCOM 
> test_kernel2.obj kmain.obj". Alink warns that it's discarding data at 
> offset... well, all of 'em... and produces a zero-length .com file. 
> That's not going to help. So tried "-oEXE". Got an .exe! Since I don't 
> have an MZ loader at hand, nor "exe2bin" (which might work), I simply 
> removed the header with a text editor. The offsets happened to work out 
> - I doubt if this will always be true! I think we're going to need a 
> proper MZ loader to handle relocations, eventually. But for now...
> 
> I combined "boot.bin" with this result using "cat", and wrote the 
> resulting "image.bin" to floppy. Wrote that to floppy with "dd". Booted, 
> and after "Welcome to the kernel", saw 'K' printed... repeatedly.
> Progress!
> 
> This isn't exactly what you want to do, but leads me to believe that, 
> with the proper tools, it may not be as difficult as I imagined. (famous 
> last words...)
> 
> Best,
> Frank
> 
> 
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